The objectives of this work are to develop new methods and strategies of carbon-carbon formation for the synthesis of biologically and medicinally important compounds. The emphasis is on the development of procedures for accomplishing multistep transformations in one pot operations. The work is divided into six sections: 1) The synthesis of polysubstituted aromatic compounds using zirconocene complexes of substituted benzynes and related species; 2) The use of zirconocene complexes of acyclic alkynes for the synthesis of cyclopentenones, 1,3-dienes, cyclobutenes as well as a variety of other useful organic compounds; 3) The use of cyclic alkyne complexes to prepare a variety of synthetically useful bicyclic compounds; 4) The synthesis of substituted cyclopropanes and cyclobutanes using zirconocene complexes of cyclopropene and cyclobutene; 5) The preparation of a variety of nitrogen containing compounds including pyrroles, pyrrolinones, lactams, allylic amines and 1,2- aminoalcohols through the vehicle of zirconocene complexes of imines; 6) The synthesis of a variety of interesting and useful organosulfur compounds using zirconocene complexes of thioaldehydes as intermediates.